The technology to form a shallow junction is demanded in recent years with the miniaturization of the semiconductor device. In the semiconductor manufacturing technology in the prior art, the method of ion-implanting various conductivity types of impurities such as boron (B), phosphorus (P), arsenic (As), and the like into a surface of a semiconductor substrate as a solid state base body at a low energy is widely employed.
Since a semiconductor device having a shallow junction is formed by using this ion-implanting method, a shallow junction can be formed actually, though there is a limit to a depth that can be formed by the ion implantation. For example, because a boron impurity is hard to dope shallowly, a limit of a depth of a doped area formed by the ion implantation is at almost 100 nm from a surface of the base body.
Therefore, recently various doping methods have been proposed as the approach of making a shallower junction possible. Out of them, much attention is now focused on the plasma doping technology as the technology that is suited to practical use. This plasma doping is the technology that excites a reaction gas containing a doped impurity by the plasma and irradiates the plasma onto a surface of the solid state base body to dope the impurity. Then, activation of the doped impurity is carried out by the annealing step after the impurity is doped.
Normally, a light source that can emit an electromagnetic wave in a wide wavelength range such as a visible radiation, an infrared radiation, a ultraviolet radiation, and the like is employed in the annealing step. However, a wavelength effective for the activation is difference depending on a crystal condition of the solid state base body itself into which the impurity is doped. Actually such wavelength often exists in a narrow range. An irradiation of the light of unnecessary wavelengths raises a temperature of the substrate and causes the characteristic deterioration in some cases.
In recent years, the method of measuring a quantity of impurity doped in a surface of a solid state base body by the optical measurement has been proposed (see JP-A-2000-282425, for example). Since this method measures a quantity of radical by the optical measurement, a doping amount can be measured by sensing an amount of current.